Air line drain valve



y 4, 1954 D. WILKIERSON AIR LINE DRAIN VALVE 3 Sheets-$h9et 1 Filed May15, 1951 ATTORNEY May 4, 1954 D. WILKERSON AIR LINE DRAIN VALVE a sheetssn et 2 Filed May 15, 1951 IN VENTOR .DEWE-Y VV/L KEESO/V ATTORNEY FiledMay 15, 1951 AIR LINE DRAIN VALVE 6 6a o 70 f i 47 e7 75 2 4.9 23

l 4 7 57 a I .HIIIIIH INVENTOR DEWEY VV/l. KEfFJ Y a s n 2 ATTORNEYPatented May 4, 1954 AIR LINE DRAIN VALVE Dewey Wilkerson, Denver,(3010., assignor to Wilkerson Corporation, Denver, 0010., a corporationof Colorado Application May 15, 1951, Serial No. 226,393

1 Claim. 1

This invention relates to the cleaning of air in compressed air lineinstallations for the purpose of removing moisture, sludge, oil andforeign matter. it provides, particularly, a drain valve that operatesautomatically to accomplish its function.

An object of the invention is to provide a snap action pressurediiierential operated drain valve adapted for coupling in any type ofcompressed air or fluid pressure installation, and which operatesautomatically in response to the level of liquid accumulation in a drainsump or trap.

Another object is to provide a valve of the character indicated having aliquid level responsive actuator operative solely as a trigger meanscontrolling the establishment of a pressure diiferential which suppliesthe actual motive power by wl'uch the valve is opened. for expulsion ofwater, sludge, and foreign matter from the in stallation.

Other and incidental objects will be apparent to persons skilled in theart.

in the accompanying drawings:

Figure 1 is substantially a vertical sectional view through an aircleaner and drain valve assembly constituting an illustrative embodimentof the invention;

Figure 2 is an enlarged fragmentary sectional view of the sump drainassembly of Figure 1, partly in elevation; and Figure 3 is substantiallya vertical sectional view illustrating a detail of the mechanism.

Figure 4 is a view similar to Figure 2 but illustrating a modificationadapted for heavy duty purposes.

In the form shown in Figs. 1-3 the valve is employed to control theexpulsion of water and sediment accumulations in a sump 5 at the bot--tom of a housing 6 provided at its top with an air inlet i and an airoutlet 8 both of which are adapted for coupling in a compressed airline, not shown. The interior of the housing constitutes an airexpansion chamber 9 substantially of cylindrical form into whichincoming air is centrally directed from the inlet 1 through a conduit lcurved ot set up a vortex action in the chamber. A filter sleeve l l ofcotton or other suitable material is mounted in the top of the housingbetween a support l2 and the top wall. Air passes from the chamber 9through openings I3 in the support to the interior of the filter sleevethrough which it passes to an annular outlet chamber is around thefilter in open communication with the air outlet 8.

The sump is formed with a well 55 of considerable depth open at its topto the air expansion chamber and at its bottom through a dischargepassage E6 to the atmosphere. The passage 56 is an axial bore through afitting ll having a threaded connection into the dished bottom of thesump well. The inner end of the fitting comprises a valve seat it whichcooperates with a valve head is on the lower end portion of a verticalhollow stem 2U to close the discharge passage.

A plate 2i is secured on the top face of the sump to extend horizontallyover its well and provide support for an upstanding casing 22 having aclosed interior chamber 23 separated from the well by a flexiblediaphragm 24 that is marginally clamped between the base of the casingand the plate. The upper end portion of the valve stem 28 is secured toand extends through the diaphragm into the chamber 23 as an externallythreaded portion 25 having threaded engagement in the bore 26 of acontrol valve fitting 2T. Clamp washers 28 at opposite sides of thediaphragm cooperate with the fitting 2i and a nut 29 on the valve stemto secure the valve stem assembly to the diaphragm for movementtherewith in response to its flexion. The fitting 21 is disposedentirely Within the chamber 23, and its bore 25 opens at its upper endthrough an air passage as into the chamber above the diaphragm. Thispassage is controlled by a depending valve plug 3! on a cylinder 32mounted for reciprocation in the bore of an upwardly extending neck 33con stituting a part of the fitting. An expansion spring 34 between thecylinder and a cap 35 threaded on the upper end of the fitting neckbiases the valve 3! downwardly against a seat at the end of the passageto close the same. In the normal position of the parts the valve 3! isclosed. When the valve is open the chamber 23 is in communication withthe fitting bore 26 through a lateral passage 35 in the neck 33. Thehollow valve stem 28 is open at both ends for free air passage throughits bore when the control valve 3| is open. This stem extends at itslower end past the valve 19, which is fixed thereon, and well into thesump discharge passage IE below the valve seat It when the valve isclosed against the seat.

Well l5 of the sump is in open communication with the chamber 9 at alltimes, but communication between chamber 9 and the chamber 23 is underthe control of means responsive to liquid level in the sump. As hereshown, the liquid level responsive means comprises a buoyant member 31,such as a float, fixed on an axial sleeve 38 that is loose on the valvestem 20 and freely slidable thereon in the well of the sump. A lowerlimit of travel of the float is determined by the seating of the lowerend of the sleeve against the valve head I 9. The float is provided witha vent pipe 39 of suflicient height to extend well above the supportplate 2|, throughwhich it plays freely, when the float is in its lowestposition. Motion of the float is transmitted to a lever 48 that ispivoted at one end on a depending arm 4| of the support plate and whichat its other end has a loop terminal 42 loosely engaged between a pairof annular flange elements 33 fixed on the float sleeve. The lever 40intermediate its ends has a pivotal connection 44 to the lower end of avertical throw link 45 which at its upper end has a pivotal connection46 to one end of a rocker lever 41. This rocker lever is fulcrumed at 48intermediate its ends on an upstanding post 49 pivoted at its lower endon the top of the casing 22. The other end of the rocker lever has apivotal connection 58 to the upper end of a vertically reciprocableplunger that plays in and through an axial bore 52 in a fitting 53mounted in the top wall or" the casing 22. Above the top wall of thecasing the fitting bore 52, which has a clearance relative to theplunger 5|, opens to the air chamber 9 through a port 54 in the fitting,and beneath the top wall of the casing the bore opens through a passage55 to the chamber 23 above the diaphragm Substantially midway betweenthe port 55 and passage 55 the plunger is diametrically reduced toprovide a valve 56 which cooperates with a seat ring 51 of rubber orother suitable material mounted in the bore 52 to open and close the airpassage formed thereby.

The reduced lower end portion of the plunger extends into the chamber asa tip 58 adapted to engage and depress the adjacent outer end of anactuator lever 59 having a fulcrum 55 on the bottom of the passage 36 inthe fitting 2?. The inner end of the lever has a bowed terminal 6| incontact with the bottom of the cylinder 32 and apertured to accommodatethe control valve plug 3|.

Normal position of the parts is as shown in Figs. 1 and 2, with thevalve I9 seated and closing the sump discharge passage l5. Weight of thevalve stem assembly including the fitting 27 above the diaphragm biasesthe valve firmly closed against its seat. At the same time the openended bore of the hollow valve stem is closed at its upper end by thevalve 3| seated under the bias of its spring 34. The lowered floatdepresses the lever 4|] and correspondingly elevates the plunger 5| tolift its valve 58 from its seat 57 and hold open the passage 55, so thatair pressure on opposite sides of the diaphragm 24 is equal. While theplunger 5| is elevated its tip 58 is held spaced above the outer end ofthe actuator lever 59. The plunger is so dimensioned that when it islowered its valve 56 closes the air passage 55 before the completion ofdownward movement which continues until the tip 58 contacts anddepresses the adjacent end of the lever 59 to open the control valve 3|.During this interval between closing of the valve 56 and opening of thevalve 3| air is trapped in the chamber 23 at full line pressure.

Water separated from the line air in the chamber 9 drains to the bottomof the sump well and the float rises in response to the rise of theliquid level therein, correspondingly lifting the lever 46 to actuatethe linkage which lowers the plunger 5|. Successive increments of waterin the sump well carry the float higher and thus, through the plunger5|, close the valve 56 to cut off communication between the line chamber9 and the control valve chamber 23. Beyond this point a slight furtherrise in the liquid level brings the plunger tip 58 down to rock thelever 59 on its fulcrum and open the valve 3|. Immediately upon openingof the valve 3| the air trapped in the chamber 23 at line pressureescapes through the valve stem bore and through the sump dischargepassage [6 to the atmosphere, whereupon a pressure differential iscreated at opposite sides of the diaphragm. In response to thisdifferential, the diaphragm flexes up into the lower pressure area inthe chamber 23 and raises the stem '20 to lift the valve l9 from itsseat to open the sump discharge passage to the atmosphere. Theaccumulation of water, sludge, and other foreign matter in the sump isthen expelled through the open discharge by air at line pressure,whereupon the float drops quickly to raise the plunger 5| back to itsinitial position through the linkage described. At the start of upwardmovement of the plunger its tip 58 frees the lever 59 whereupon thespring 3 becomes effective to close the valve 3| and cut off air passagethrough the valve stem bore. Immediately following closure of the valve3| the plunger valve 58 opens to allow air at line pressure again topass to the chamber 23,. whereupon the air pressure on opposite sides ofthe diaphragm equalizes and the sump valve |9 drops back to closedposition against its seat as the diaphragm flexes downwardly to itsoriginal position.

It is apparent from the foregoing description that the invention in itsbroad aspects incorporates a pressure differential operated valvecontrolling the discharge of water accumulation in a sump open to acompressed air line, with means responsive to liquid level in the sumpto create and abolish the pressure differential by which the sump valveis actuated. No part of the liquid level responsive means has anymechanical operating connection with the sump valve assembly, so thatoperation of the liquid level responsive means is unhampered in thatrespect.

The embodiment of the invention as shown in Fig. l is essentially thesame as that of the preceding form both in structure and operation, andthe same reference characters are employed to indicate the same parts inthe several views. In the Fig. 4 form, however, the sump 5a constitutesthe lower section of a two-part casing whereof the upper sectionconsists of a dome cover 62, the interior of which provides a chamber 63in open communication with the sump well it. The sump and cover areprovided with meeting end flanges clamped together against a sealinggasket M by suitable securing means 65, whereby the connected sump andcover together comprise a unit for connection with a drainage source,not shown, such as a compressed air line sump, air tank, after-cooler,or other fluid pressure instal lation, through an inlet passage 65' inthe top of the cover.

Further, in this embodiment of the invention, the support plate 2|itself constitutes a wall closing and sealing the bottom of the chamber23 in the casing 22" above the support plate. This casing 22' has a boss61 on its top wall provided with a bore axially aligned with the inlet56 and having threaded engagement with a bolt stem 68 which constitutesa stop member extending into the chamber 23 for vertical adjustmenttherein. A look nut 69 maintains a set adjustment of the stem and servesto anchor the lateral foot flange ill of a shield plate ii which extendsabove and over the upper end of the 5i and rocker lever ll to protectthese elements against movement or injury by impact of solid particlespassed through the inlet Also, in this embodiment of the invention, thecontrol valve fitting 27 secured on the upper end of the hollow valvestem 253 is formed as a piston for vertical reciprocation in a cylinderbushing 12 which opens axially through the plate 2|. An annular packingring i3 surrounds the piston in a groove in the cylinder to preventpassage of fluid past the piston. The cap nut 35' on the piston fitting2? has an upward axial stud id for abutment against the lower end of thestop stem 65 to limit upward travel of the piston, and the piston isbiased downwardly by an expansion spring 55 surrounding the stud andstem between the cap nut and the top wall of the casing 22. The ventedfloat of the Fig. 2 form is in this instance substituted by a ball float31a as being better suited to its intended uses.

In service, the inlet 65 is connected in open communication with adrainage source so that the chamber 53 and sump well l5 are subjected tothe existing fluid pressure of the installation with which theconnection is made. The unit is designed particularly for heavy dutyunder severe sludge conditions and is adapted, by use of proper heat andcold resistant materials in the discharge valve is and packing is, forsteam applications, or for sub zero installations, as well as for normaltemperature drains. Under some intended operating conditions, smallrocks, pebbles, and sand as well as sludge and water have to be drainedfrom the installation. So long as the exposed effective area of thepiston is kept substantially larger than the cross sectional area of thedischarge passage [6, as shown, the passage can be any size desired; andby adjustment of the stop member 68 a corresponding adjustment of theopening extent of the discharge control valve 59 can be efiected.

In the normal position of the parts, as shown in Fig. 4, the valves i9and SI are closed and the plunger valve 55 is open, so that the unit isclosed to the atmosphere and the chambers 23 and 63 are in opencommunication with pressure equal above and below the piston 27'. As thefloat 31a rises in response to accumulation of liquid in the sump, thelinkage operates to depress plunger 5| to close the valve 56 and thenopen the valve 3|. In the several views of the drawings the valve 3|appears slightly open, for clearness of illustration; its normalposition is fully closed. Immediately upon opening of valve 3! thechamber 23 vents to the atmosphere through the hollow valve stem 20,whereupon the greater pressure on the bottom of the piston forces it upin the cylinder bushing 12 to the extent permitted by the stop 63 toopen the sump discharge valve l9, whereupon the accumulated matter inthe sump is expelled to the atmosphere under the existing pressure ofthe installation. The float then falls and the linkage operates to liftthe plunger 5i to close the valve 3! and then open the valve 56 forequalization of pressure in the chambers 63 and 23 and at both ends ofthe piston. Spring then forces the piston and stem 20 downwardly toclose the sump discharge valve l9, whereupon the unit is conditioned foranother cycle of operation in the manner described.

It is to be understood that although the instant disclosure isillustrative of certain embodiments by which the invention is reduced topractice, any desired changes and modifications consistent with thescope of the invention as claimed may be made in the details of thestructure as shown.

I claim:

A compressed air line drain valve comprising a casing having an airinlet chamber provided with a sump having a water outlet, a secondchamber, a movable member separating said chambers and movable inresponse to a pressure difierential therebetween, a stem assemblysecured to said movable member for movement therewith, a valve fixed onthe stem controlling the water outlet and biased to closed position,said stem having an air passage therethrough open at one end to saidsecond chamber and at its other end to the atmosphere, said secondchamber having an air passage in a fixed wall thereof establishingcommunication with the air inlet chamber, a normally open valvecontrolling said chamber air passage, means movable in response toliquid level in the sump to actuate the chamber air passage valve toopen and closed positions, a valve in said second chamber controllingthe stem air passage and biased to a normally closed position, and meansoperable by said chamber air passage valve in closing to open said stemair passage valve for escape of air from said second chamber to create apressure differential at opposite sides of the movable member andthereby move said valve stem to open the sump water outlet valve.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 347,856 Wiedling Aug. 24, 1886 570,893 Donnelly Mar. 26, 1901779,772 Donnelly Jan. 10, 1905 1,955,495 Hack Apr. '7, 1934 FOREIGNPATENTS Number Country Date 848 Great Britain of 1896 14,797 GreatBritain of 1914

